Serial downvoting

So, 11 hours ago, 6 of my answers were downvoted all at the same time. Now, the serial downvoting was reversed, which means 5 out of 6 of the downvotes were reversed. Why only 5 out of 6? If it is clear that someone is just downvoting to downvote, shouldn't all of them be reversed? The person who downvoted gave all downvotes to questions with 0 votes, so now I'm stuck with an accepted answer with 1 downvote and no upvotes. This isn't a huge deal but it makes it seem like it's a bad answer when at least the OP found it helpful.

And, mods can't tell who did this, right?

• It seems that down-vote on your CW answer was not reversed either. (As we do not know details about how the detection script works, we cannot be sure that it is part of the serial downvoting; but on the reputation tab in your profile this answer is shown after the one you have linked to.) – Martin Sleziak Oct 29 '12 at 13:21

• For the record, these are the times as shown in OP's reputation tab Not reversed: 00:58:51 Probably not reversed (CW) 01:00:02 Reversed: 01:00:12 01:00:24 01:00:44 01:00:50 01:00:54\\ I don't know whether it is possible to find out for sure whether the downvote for the CW answer has been reversed or not. (It is possible that the downvote I see there now have been there already before this.) – Martin Sleziak Oct 29 '12 at 13:29